Exhaust gas after treatment systems are commonly used in conjunction with diesel engines for reducing the amount of nitrous oxides (NOx) in an exhaust gas. A typical configuration of the system has a reservoir filled with the treatment fluid, such as ammonia, fuel or urea, which is transported to a dosing injector, including, but not limited to a pump. The dosing injector sprays the treatment fluid into the exhaust gas prior to transport into a catalytic converter. The nitrous oxides in the exhaust gas are reduced when they react with the treatment fluid and are converted into water and nitrogen. After reacting in the catalytic converter, the exhaust gas is released from the catalytic converter into the atmosphere.
The use of diesel engines can range from small vehicles to large tractor-trailer truck applications. Due to the large variety of vehicles, the dosing requirements will vary due to different fuel pressures, flow rates, and required accuracy of the system. It is desirable to have a system for distributing the treatment fluid between the reservoir and injector which can easily accommodate various combinations of pressure relief, regulator, and on/off valves to provide scalability for the different dosing applications.
Additionally, the transfer of fluid poses the potential for leakage, both internally and externally. When a pump is used to move the treatment fluid, it can create significant pressure against system components, such as closed valves. As a result, these closed valves may leak, allowing fluid to pass. Such internal leakage can produce undesirable parasitic losses and can compromise leak detection accuracy. External leakage may pose safety concerns, harm the environment, and can damage system components. Thus, it is also desirable that the dosing manifold assembly be able to detect both internal and external system leaks.